Mary and her daughter's donation to the fund is separate from the South African Future Trust initiative launched by her brother Nicky last week.

Mary and Nicky are the children of the late mining magnate Harry Oppenheimer. He was the former chairman of Anglo American and De Beers. He died in 2000.

"My daughters and I have thought long and hard about where we could make the greatest difference in this fight and have decided it is to support the humanitarian needs of everyone living in South Africa. So, we think that it is the Solidarity Fund which is most aligned to our concerns about basic needs, food, medicine, general care and gender abuse."